Oscillatory Networks of High-Level Mental Alignment: A Perspective-Taking MEG Study

Abstract

Mentally imagining another’s perspective is a high-level social process, reliant on manipulating internal representations of the self in an embodied manner. Recently Wang et al., (1) showed that theta-band (3-7Hz) brain oscillations within the right temporo-parietal junction (rTPJ) and brain regions coding for motor/body schema contribute to the process of perspective-taking. Using a task requiring participants to engage in embodied perspective-taking, we set out to unravel the extended functional brain network and its connections in detail. We found that increasing the angle of disparity between self and other perspective was accompanied by longer reaction times and increases in theta power within rTPJ, right lateral pre-frontal cortex (PFC) and right anterior cingulate cortex (ACC). Using nonparametric Granger-causality, we showed that during later stages of perspective-taking, the lateral PFC and ACC exert top-down influences over rTPJ, indicative of executive control processes required for managing conflicts between self and other perspectives. Finally, we quantified patterns of whole-brain phase coupling (imaginary coherence) in relation to rTPJ during high-level perspective taking. Results suggest that rTPJ increases its theta-band phase synchrony with brain regions involved in mentalizing and regions coding for motor/body schema; whilst decreasing its synchrony to visual regions. Implications for neurocognitive models are discussed, and it is proposed that rTPJ acts as a ‘hub’ to route bottom-up visual information to internal representations of the self during perspective-taking, co-ordinated by theta-band oscillations. The self is then projected onto the other’s perspective via embodied motor/body schema transformations, regulated by top-down cingulo-frontal activity.Significance Statement: High-level social processing, such as the ability to imagine another’s visuospatial experience of the world (perspective taking), is a core part of what makes us human. Building on a substantial body of converging previous evidence, our study reveals how concerted activity across the cortex in low frequencies (theta: 3-7 Hz) implements this crucial human process. We found that oscillatory power and connectivity (imaginary coherence, nonparametric Granger causality) at theta frequency linked functional sub-networks of executive control, mentalizing, and sensorimotor/body schema via a main hub located in the right temporo-parietal junction (rTPJ). Our findings inform neurocognitive models of social cognition by describing the co-ordinated changes in brain network connectivity, mediated by theta oscillations, during perspective-taking.